Is Funduscopy Clinically Useful in the Evaluation of the Hypertensive Patient?

In the last two decades, all disciplines of medicine have witnessed a surge of emphasis on evidence‐based medicine. Increasingly, components of the physical examination that had traditionally been viewed as essential are being scrutinized under the magnifying glass of “clinical evidence.” Consequently, practitioners who are under considerable time constraints are condensing their physical exams, deleting those items that lack sufficient data supporting their routine use. This raises the issue of whether examination of the retina is clinically useful in the evaluation of the hypertensive patient.

In 1850, Hermann von Helmholtz invented the ophthalmoscope. Nine years later Liebreich was the first to describe abnormalities of the retina in a patient with probable hypertension. Subsequently, the spectrum of hypertensive retinopathy was described to include grades I (focal arteriolar constriction), II (generalized arteriolar constriction), III (flame‐shaped hemorrhages, cotton wool spots, and yellow‐white exudates), and IV (papilledema accompanied by hemorrhages and exudates). More recently, a revised classification of hypertensive retinopathy has been proposed, consisting of only two grades: I (arteriolar narrowing, focal constriction, and arteriovenous nicking) and II (hemorrhages and exudates, with or without disc edema). ¹ It is often difficult to detect early change of grade I retinopathy, i.e., focal constriction or arteriolar narrowing.

The prevalence of hypertensive retinopathy has only recently been described. The Beaver Dam Eye Study ¹ and the Blue Mountains Eye Study ³ have reported a prevalence of retinopathy of 8%–10% among nondiabetic hypertensive patients. The incidence increases with age and severity (or poor control) of hypertension.

The clinical significance of hypertensive retinopathy was not apparent until 1939, when a group of physicians at the Mayo Clinic classified hypertensive patients based on the severity of retinal disease and showed that those with more severe disease had higher morbidity and mortality. Subsequent reports have shown a correlation between the presence of hypertensive retinopathy and lower glomerular filtration rates as well as with the presence of left ventricular hypertrophy.

Though there are case reports of hypertensive retinopathy progressing to blindness, ⁴ either directly (via retinal infarction, retinal hemorrhage, disc edema, or vitreous hemorrhage) or indirectly (via infarction of the visual cortex or optic nerve, occlusion of retinal vessels, or raised intracranial blood pressure), hypertensive retinopathy is not a major cause of blindness. Most of the case reports are in patients with severe, malignant hypertension, including those whose blood pressures were lowered too rapidly.

Thus, hypertensive retinopathy might be viewed as more of a marker for other cardiovascular outcomes, rather than as a true cardiovascular outcome in its own right. It is grouped together with “true” cardiovascular outcomes under the category of “target organ damage” in the seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7), though the authors recommend antihypertensive therapy based on blood‐pressure level without regard to the presence or absence of hypertensive retinopathy. Some authors, however, do recommend more aggressive blood pressure control in the presence of hypertensive retinopathy.⁶ For example, in a patient with prehypertension, the presence of hypertensive retinopathy might prompt one to be more aggressive about instituting blood pressure reducing measures or more careful about monitoring blood pressure. To date, there is no evidence that controlling blood pressure more aggressively than recommended by JNC 7 will improve outcomes. Furthermore, even if such evidence did exist, there is no reason to assume that funduscopy would be more sensitive than other markers for cardiovascular outcomes such as presence of left ventricular hypertrophy or elevated creatinine. Nevertheless, funduscopy is noninvasive and takes only seconds to perform in experienced hands. Furthermore, routine performance of funduscopy will increase one's proficiency in this maneuver, which is required in certain circumstances, such as malignant hypertension or diabetes. Thus, we do recommend funduscopy in the evaluation of the hypertensive patient. Although some cases of grade I retinopathy may be missed, the finding, if present, may be helpful in determining the urgency of treatment.